Photoluminescence and Stoichiometry Correlation in Nanocrystalline EuO(x) Thin Films: Tunable Color Emission

[Image: see text] The development of broadband and ultracompact optoelectronic devices relies on the possibility of fabricating bright and tunable emitters at the nanoscale. Here, we show emission from EuO(x) (1 ≤ x < 1.4) thin films on silicon formed by nanocrystals with average sizes in the range of 5 nm. The photoluminescence emission of the nano-EuO(x) films is tunable as a function of the oxygen concentration changing from a green broadband Eu(2+)-related emission to a narrow red Eu(3+)-related emission. To reach these results has been instrumental through the use of a new methodology specially designed to achieve high-quality europium oxide films whose compositional properties are controlled by the growth base pressure and preserved thanks to a chemically stable and transparent cover layer of Al(2)O(3). Our findings confirm the outstanding potential of nanostructured EuO(x) films as “one-compound” optical elements with tunable emission properties for their implementation in integrated silicon-based devices.